Process of refining distilled grease.



NITED STATES PATENT Erica.

JOHNIIOPKINSON, OF BRADFORD, ENGLAND.

SPECIFICATION forming part of Letters Patent No. 645,623, dated March20, 1900.

Application filed August 17, 1398- Serial No; 688,795. (No specimens.)

To all z uhmn it may concern:

Be it known that 1, JOHN HOPKINSON, asubject of the Queen of GreatBritain, residing at Bradford, in the county of York, England,

' perheated steam.

have invented certain new and useful Improvements in the Treatment ofDistilled Grease, of which the following is a specification.

This'invention is applicable to greases obtained by distillingoleaginous matterswith su- In the distillation of these greases thematerial is split up chemically and the distillate is found to consistof oleic and stearic acids (and sometimes other acids, depending on thematter distilled) dissolved in or combined with matters consistingentirely of carbon and hydrogen and which I will hereinafter call theresidual products. It has hitherto been found impracticable to separatethe fatty acids from the residual products, as they distil substantiallyat the same temperature, and if the acids be saponified the residualproducts dissolve in the soap and spoil it.

Now this invention is designed to separate the residual products fromthe fatty acids and obtain both in a salable form. I find that if thesaponifiable matters in the grease be saponified with a slight excess ofcaustic alkali the resulting soap is soluble in dilute alcohol, whilethe residual products are not. These latter therefore separate and riseto the surface on the whole being allowed to stand. The separation isnot, however, complete; but if another light hydrocarbon insoluble indilute alcohol-such, for instance, as benzol be added this greatlyassists the heavier residual products to rise and separate from the soapsolution. If, however, the benzol be added at first, a much largeramount of benzol is required to be added than when as much of theresidual products as will easily separate without it are separatedfirst. In the last instance all the benzol can be used for diluting thesmall residual quantity of hydrocarbon. Consequently much less isrequired than if the benzol be added with the alcohol.

In carrying out my invention I take distilled grease-that is, the greasewhich is distilled over and condensed when animal or vegetable oils orgreases are distilled (see Campbell Morfits book, published by Parry &McMillan, of Philadelphia, in 1856, page 485, et sequitu -r)and saponifythe saponifiable matters in it by a slight excess of a solution ofcaustic alkali and add to it about three and a half times its bulk ofethyl or methyl alcohol or methylated spirits, (which is a combinationof the two largely used in England,) and I allow the mixture to stand.The alcohol is added, as combined with the water of the saponified massit will dissolve the soap, but will not dissolve the residual products.A large proportion of the residual products consequently rise, beinglighter than the solution of soap, and they are now skimmed off, as byso doing less benzol is required in the next step of the process than ifthey were allowed to stand, and consequently allowed to dilute thebenzol. When the hydrocarbon oil ceases to rise freely and what hasrisen has been skimmed off, coal-tar benzol or other light hydrocarbonsolvent is added a little at a time and agitated with the soap. By thusagitating it-with the soap the remaining residual products which aremechanically mixed with the soap in a state of fine division or emulsionare enabled to combine with it, and the benzol, being exceedinglylight,.assists in buoying up the residual products to the surface. Theseresidual products and the benzol in solution are next skimmed off andfurther benzol added with agitation and again skimmed off and theprocess continued until all the residual products have been removed fromthe soap. The soap is now freed from the spirits by distillation and isready for finishing in ordinary course. In practice benzol to aboutone-fourth of the bulk of the impure soap operated upon is used. Thesolution of residual products is also freed from the benzol or otherlight hydrocarbon by distillation and is a valuable machinery-oil; thelight distillate being used again for separating further residualproducts in the first part of the process. Instead, however, offinishing the soap as above mentioned I may, if

desirable, acidify it with an excess of mineral or organic acid in themanner well known, and thus obtain a mixture of stearic and oleic acidand a solution of the soda salt of the mineral or organic acid which wasadded. The mixture of stea'ric or oleic acid, which is much lighter thanthe salt solution, and consequently floats on the top, is in such caseskimmed ofi, is crystallized in bulk, and is submitted to hydraulicpressure to separate the solid stearic acid from the liquid oleic acid.The latter is known in commerce as olein. The solid stearic acid is nowready for the manufacture of candles, and the olein can be used forlubricating wool or for making soap or for any other purposes for whichit is now applied.

I declare that What I claim is 1. The treatment of distilled greasecontaining unsaponifiable matter which consists in treating them with asolution of caustic alkali and ethyl or methyl alcohol, skimming ofi theresidual products which rise and adding a little at a time withagitation to the remainder a solution of light hydrocarbon such ascoal-tar benzol insoluble in methyl or ethyl alcohol and distilling eachsolution separately, substantially as described.

2. The process of obtaining soap from distilled or other greasecontaining unsaponifiable matter which consists in fully saponifyin gwith caustic alkali adding methyl or ethyl alcohol whereby the residualproducts become insoluble in the soap and separating the residualproducts substantially as described, distilling off the spirits andfinishing the soap.

3. The process of separating residual prod ucts from distilled greasewhich consists in fully saponifying the saponifiable matter in thegrease, dissolving the same in methyl or ethyl alcohol whereby thegreater portion of the residual products separate and float on thesurface and can be skimmed off and separating the remainder of theresidual products by adding a light hydrocarbon such as benzol insolublein dilute spirits a little at a time with agitation and skimming 0E, andseparating the light residual products from the heavier ones bydistillation whereby they can be used again in the first operation.

In witness whereof I have hereunto signed my name, this 3d day ofAugust, 1898, in the presence of two subscribing witnesses.

JOHN I'IOPKINSON.

Witnesses:

WILLIAM SERNTON, DAN OoATEs.

